1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
import numpy as np

NN = np.uint64(1e9 + 7)

def quick_pascal_sum(n):
    NNN = NN
    qp = np.zeros((n, 3), dtype=np.uint64)
    qp[0, 0] = 1
    for row in range(1, n):
        qp[row, 0] = (qp[row-1, 0] + qp[row-1,-1]) % NNN
        qp[row, 1] = (qp[row-1, 1] + qp[row-1, 0]) % NNN
        qp[row, 2] = (qp[row-1, 2] + qp[row-1, 1]) % NNN
    return qp


def quick_check(c, z):
    return c % 3 != z % 3

def swap(s):
    if s == b'c'[0]:
        return b'z'[0]
    if s == b'z'[0]:
        return b'c'[0]
    raise ValueError


def can_be_interleaving(s, start_letter):
    next_letter = start_letter
    for c in s:
        if c == b'n'[0]:
            next_letter = swap(next_letter)
            continue
        if c == next_letter:
            next_letter = swap(next_letter)
        else:
            return False
    return True

C = ord('c')
Z = ord('z')
N = ord('n')

def check_me(n, c, z, even, odd):
    global qp
    TOTAL = np.int64(0)

    for k in range(3):
        if quick_check(c+k, z+n-k):
            # print(k, qp[n, k])
            TOTAL += qp[n, k]
            TOTAL %= NN

    n_letters = n+c+z

    if n_letters % 2 == 1:
        half = n_letters // 2
        # CZCZCZC 
        # CNNNNNC 
        oddC = odd[C] + odd[N]
        evenC = even[C] + even[N]

        oddZ = odd[Z] + odd[N]
        evenZ = even[Z] + even[N]

        if oddC == half + 1 and evenZ == half:
            TOTAL += NN - 1
            TOTAL %= NN
        if oddZ == half + 1 and evenC == half:
            TOTAL += NN - 1
            TOTAL %= NN

    return int(TOTAL)


NUM, Q = list(map(int, input().strip().split(' ')))
S = bytearray(input().strip().lower(), 'ascii')

qp = quick_pascal_sum(NUM+1)

from collections import defaultdict
odd  = { N: 0, C: 0, Z: 0 } 
even =  { N: 0, C: 0, Z: 0 } 

for i, c in enumerate(S):
    if (i+1) % 2 == 0:
        even[c] += 1
    else:
        odd[c] += 1

counters = {
    N : S.count(b'n'),
    C : S.count(b'c'),
    Z : S.count(b'z')
}

print(check_me(counters[N], counters[C], counters[Z], even, odd))

for q in range(Q):
    line = input().strip().split(' ')
    idx = int(line[0])
    letter = bytearray(line[1].lower(), 'ascii')[0]
#
    old_letter = S[idx-1]
    S[idx-1] = letter

    if idx % 2 == 0:
        even[old_letter] -= 1
        even[letter] += 1
    else:
        odd[old_letter] -= 1
        odd[letter] += 1

    counters[old_letter] -= 1
    counters[letter] += 1

    print(check_me(counters[N], counters[C], counters[Z], even, odd))