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//Franciszek Witt
#include<bits/stdc++.h>
using namespace std;
#define FOR(i,l,r) for(int i=(l);i<=(r);++i)
#define REP(i,n) FOR(i,0,(n)-1)
#define ssize(x) int(x.size())
template<class A,class B>auto&operator<<(ostream&o,pair<A,B>p){return o<<'('<<p.first<<", "<<p.second<<')';}
template<class T>auto operator<<(ostream&o,T x)->decltype(x.end(),o){o<<'{';int i=0;for(auto e:x)o<<(", ")+2*!i++<<e;return o<<'}';}
#ifdef DEBUG
#define debug(x...) cerr<<"["#x"]: ",[](auto...$){((cerr<<$<<"; "),...);}(x),cerr<<'\n'
#else
#define debug(...) {}
#endif
typedef long long ll;
typedef long double ld;

struct rt {
    ll p, q;
};

rt norm(rt a) {
    ll gg = __gcd(a.p, a.q);
    rt tmp =  rt({a.p / gg, a.q / gg});
    if(tmp.p < 0) {
        tmp.p = -tmp.p;
        tmp.q = -tmp.q;
    }
    return tmp;
}

rt operator * (rt a, rt b) {
    return norm(rt({a.p * b.p, a.q * b.q}));
}

rt operator + (rt a, rt b) {
    return norm(rt{a.p * b.q + b.p * a.q, a.q * b.q});
}

rt operator - (rt a, rt b) {
    return norm(rt{a.p * b.q - b.p * a.q, a.q * b.q});
}


void n1(int m) {
    string s;
    cin >> s;
    rt ow = {0LL, 1LL};
    rt ok = ow;
    rt od = ow;
    auto eval = [&] (int x) {
        if(x < 0 || x >= m)
            return rt({0LL, 1LL});
        char c = s[x];
        if(c == '.')
            return rt({0LL, 1LL});
        else if(c == 'O')
            return rt({1LL, 1LL});
        else
            return rt({1LL, 2LL});
    };
    auto ne = [&] (rt x) {
        return (rt({1LL, 1LL}) - x);
    };
    REP(i, m) {
        ow = ow + eval(i);
        ok = ok + eval(i) * eval(i - 1);
        od = od + ne(eval(i - 1)) * eval(i) * eval(i + 1) * ne(eval(i + 2));
    }
    rt w = ow - ok - od;
    cout << w.p << "/" << w.q << endl;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m;
    cin >> n >> m;
    if(n == 1) {
        n1(m);
        return 0;
    }
}