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#include <bits/stdc++.h>
using namespace std;
constexpr long MOD = 1e9 + 7;

int length, updates, redNumber, greenNumber, blueNumber, oddRedNumber, oddGreenNumber;
char* particles;
int diff[2][3][3] = {1, 0, 0, 0, 0, 1, 0, 1, 0,
                     -1, 0, 0, 0, 0, -1, 0, -1, 0};
int* pascal = new int[200000];

void countColors(int index) {
    if (particles[index] == 'N') {
        blueNumber++;
    }
    if (particles[index] == 'Z') {
        greenNumber++;
        if (index % 2 == 1) {
            oddGreenNumber++;
        }
    }
    if (particles[index] == 'C') {
        redNumber++;
        if (index % 2 == 1) {
            oddRedNumber++;
        }
    }
}

int getAlternatingNumber() {
    if (length % 2 == 0) {
        return 0;
    }
    if (length < 2) {
        return 0;
    }
    if (length == blueNumber) {
        return 2;
    }
    if ((oddGreenNumber == 0 && redNumber == oddRedNumber) || (oddRedNumber == 0 && greenNumber == oddGreenNumber)) {
        return 1;
    }
    return 0;
}

long twoToPower(int number) {
    long result = 1;
    for (int i = 0; i < number; ++i) {
        result = (result * 2) % MOD;
    }
    return result;
}

long plusMod(long x, long y) {
    return (MOD + x + y) % MOD;
}

long divideByThree(long x) {
    return (x * 333333336) % MOD;
}

int newRed() {
    return (3 - ((2*redNumber + blueNumber + greenNumber) % 3)) % 3;
}

int getSubsetsNumber(int xxx, int yyy) {
    return (int) plusMod(pascal[xxx-1], -diff[xxx % 2][xxx % 3][yyy]);
}

void compute() {
    int alternatingNumber = getAlternatingNumber();
    int subsetsNumber = getSubsetsNumber(blueNumber, newRed());
    int result = subsetsNumber - alternatingNumber;
    cout << result << endl;
}

void update() {
    int index;
    cin >> index;
    index--;
    if (particles[index] == 'C') {
        redNumber--;
        if (index % 2 == 1) {
            oddRedNumber--;
        }
    }
    if (particles[index] == 'Z') {
        greenNumber--;
        if (index % 2 == 1) {
            oddGreenNumber--;
        }
    }
    if (particles[index] == 'N') {
        blueNumber--;
    }
    cin >> particles[index];
    countColors(index);
}

void computePascal() {
    long result = 1;
    long power = 2;
    bool plusOne = false;
    pascal[0] = 1;
    for (int i = 1; i <= 200000; ++i) {
        power = (power * 2) % MOD;
        result = (2 * result + (plusOne ? 1 : -1)) % MOD;
        plusOne = !plusOne;
        pascal[i] = (int)((MOD + power - result) % MOD);
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    computePascal();

    cin >> length >> updates;

    particles = new char[length];
    for (int i = 0; i < length; ++i) {
        cin >> particles[i];
        countColors(i);
    }
    compute();
    for (int i = 0; i < updates; ++i) {
        update();
        compute();
    }

    return 0;
}