#pragma GCC optimize("Ofast")
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long; 
using pii =  pair<int, int>;
using pll =  pair<long long, long long>;
#define rep(i, n) for(int i = 0; i < (n); ++i)
#define all(x) (x).begin(),(x).end()
constexpr char ln =  '\n';
constexpr long long MOD = 1000000007LL;
//constexpr long long MOD = 998244353LL;
template<class T, class U> inline bool chmax(T &a, U b) { if (a < b) { a = b; return true;} return false; }
template<class T, class U> inline bool chmin(T &a, U b) { if (a > b) { a = b; return true;} return false; }
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////


template <std::uint_fast64_t Modulus> 
struct ModInt {
    using u64 = std::uint_fast64_t;

    u64 a;

    constexpr ModInt(const long long x = 0) noexcept : a(x >= 0 ? x % Modulus : (Modulus - (-x) % Modulus) % Modulus) {}
    constexpr u64 &value() noexcept { return a; }
    constexpr const u64 &value() const noexcept { return a; }
    constexpr ModInt operator+(const ModInt rhs) const noexcept {return ModInt(*this) += rhs;}
    constexpr ModInt operator-(const ModInt rhs) const noexcept {return ModInt(*this) -= rhs;}
    constexpr ModInt operator*(const ModInt rhs) const noexcept {return ModInt(*this) *= rhs;}
    constexpr ModInt operator/(const ModInt rhs) const noexcept {return ModInt(*this) /= rhs;}
    constexpr ModInt operator^(const long long rhs) const noexcept {return ModInt(*this) ^= rhs;}
    constexpr ModInt &operator+=(const ModInt rhs) noexcept {
        a += rhs.a;
        if (a >= Modulus) {
            a -= Modulus;
        }
        return *this;
    }
    constexpr ModInt &operator-=(const ModInt rhs) noexcept {
        if (a < rhs.a) {
            a += Modulus;
        }
        a -= rhs.a;
        return *this;
    }
    constexpr ModInt &operator*=(const ModInt rhs) noexcept {
        a = a * rhs.a % Modulus;
        return *this;
    }
    constexpr ModInt &operator/=(ModInt rhs) noexcept {
        u64 exp = Modulus - 2;
        while (exp) {
            if (exp % 2) {
                *this *= rhs;
            }
            rhs *= rhs;
            exp /= 2;
        }
        return *this;
    }
    constexpr ModInt &operator^=(long long exp) noexcept {
        ModInt b = a;
        a = 1;
        while (exp) {
            if (exp&1) *this *= b;
            exp >>= 1;
            b *= b;
        }
        return *this;
    }

    bool operator==(const ModInt &p) const {return a == p.a;}
    bool operator!=(const ModInt &p) const {return a != p.a;}

};

using mint = ModInt<MOD>;

int main() {
    ios::sync_with_stdio(false); cin.tie(nullptr);
    int N,M; cin >> N >> M;
    string S; cin >> S;
    vector<int> L(M),R(M);
    rep(i,M) {
        cin >> L[i] >> R[i];
        --L[i]; --R[i];
    }
    vector<int> cnt(N+1);
    rep(i,N) {
        if (S[i]=='0') cnt[i+1] = 1;
        cnt[i+1] += cnt[i];
    }

    int r = 0;
    int cur = 0;
    vector<vector<mint>> dp(N+1, vector<mint>(N+1));
    dp[0][0] = 1;
    rep(i,N) {
        while (cur < M and L[cur]==i) {
            chmax(r,R[cur]);
            cur++;
        }
        rep(j,N+1) {
            if (i+1-j <= r+1-cnt[r+1]) dp[i+1][j] += dp[i][j];
            if (j <= cnt[r+1] and j) dp[i+1][j] += dp[i][j-1];
        }
        if (r==i) r++;
    }

    cout << dp[N][cnt[N]].a << ln;
}

Measured memory_bytes: 70784