#include "bits/stdc++.h"
using namespace std;
typedef long long li;


template <long long mod>
struct modint {
    long long x;

    modint<mod>(): x(0LL) {}
    modint<mod>(const long long _data) {
        if (_data < 0) {
            x = (_data % mod + mod) % mod;
        } else if (_data >= mod) {
            x = _data % mod;
        } else {
            x = _data;
        }
    }

    bool operator==(const modint<mod>& op) const {
        return x == op.x;
    }

    bool operator!=(const modint<mod>& op) const {
        return !((*this) == op);
    }

    modint<mod> operator-() const {
        if (x == 0) {
            return modint(0);
        }
        return modint(mod - x);
    }

    modint<mod> operator+(const modint<mod>& op) const {
        const long long newdata = x + op.x;
        if (newdata >= mod) {
            return modint<mod>(newdata - mod);
        } else {
            return modint<mod>(newdata);
        }
    }

    modint<mod> operator-(const modint<mod>& op) const {
        return *this + (-op);
    }

    modint<mod> operator*(const modint<mod>& op) const {
        return modint<mod>(x * op.x % mod);
    }

    modint<mod> pow(const long long n) const {
        if (n == 0) {
            return modint<mod>(1);
        }
        modint<mod> sq = pow(n / 2);
        if (n & 1) {
            return (*this) * sq * sq;
        } else {
            return sq * sq;
        }
    }

    modint<mod> inverse() const {
        return pow(mod - 2);
    }

    modint<mod> operator/(const modint<mod>& op) const {
        return (*this) * op.inverse();
    }

    friend modint<mod> operator/(const long long dividend, const modint<mod>& divisor) {
        return modint<mod>(dividend) / divisor;
    }

    static modint<mod> factorial(const long long n) {
        static std::vector<modint<mod>> cache(1, 1);

        while (cache.size() <= n) {
            modint<mod> next = cache.back() * cache.size();
            cache.push_back(next);
        }
        return cache[n];
    }

    static modint<mod> combination(const long long n, const long long k) {
        if (k < 0 || n < k) {
            return modint<mod>(0);
        }

        if (n < 1e6) {
            return factorial(n) / (factorial(k) * factorial(n - k));
        }

        modint<mod> ret(1);
        for (int i = 1; i <= k; ++i) {
            ret = ret * modint<mod>(n - i + 1) / modint<mod>(i);
        }
        return ret;
    }
};

typedef modint<1000000007> mint;


int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);

    li n, m;
    cin >> n >> m;
    string s;
    cin >> s;
    vector<li> ops(n);
    for (int i = 0; i < m; ++i) {
        li l, r;
        cin >> l >> r;
        l--; r--;
        ops[l] = max(ops[l], r);
    }

    vector<li> accum(n + 1);
    for (int i = 0; i < n; ++i) {
        accum[i + 1] = accum[i] + (s[i] - '0');
    }

    vector<vector<mint>> dp(n + 1, vector<mint>(n + 1, 0));
    dp[0][0] = 1;
    li max_r = 0;
    for (int i = 0; i < n; ++i) {
        max_r = max(max_r, ops[i]);
        max_r = max(max_r, (li) i);
        const li ones = accum[max_r + 1];
        const li zeros = max_r + 1 - ones;
        for (int next_ones = 0; next_ones <= ones; ++next_ones) {
            const li next_zeros = i + 1 - next_ones;
            if (next_zeros < 0 || next_zeros > zeros) {
                continue;
            }
            dp[i + 1][next_ones] = dp[i][next_ones];
            if (next_ones > 0) {
                dp[i + 1][next_ones] = dp[i + 1][next_ones] + dp[i][next_ones - 1];
            }
        }

    }

    cout << dp[n][accum[n]].x << endl;
    return 0;
}

Measured memory_bytes: 70784