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

template<uint_fast64_t Modulus> class modint{
    using u64=uint_fast64_t;
    public:
    u64 a;
    constexpr modint(const u64 x=0) noexcept:a(((x%Modulus)+Modulus)%Modulus){}
    constexpr u64 &value() noexcept{return a;}
    constexpr const u64 &value() const noexcept{return a;}
    constexpr modint &operator+=(const modint &rhs) noexcept{
        a+=rhs.a;
        if (a>=Modulus) a-=Modulus;
        return *this;
    }
    constexpr modint operator+(const modint &rhs) const noexcept{
        return modint(*this)+=rhs;
    }
    constexpr modint &operator++() noexcept{
        return ++a,*this;
    }
    constexpr modint operator++(int) noexcept{
        modint t=*this; return ++a,t;
    }
    constexpr modint &operator-=(const modint &rhs) noexcept{
        if (a<rhs.a) a+=Modulus;
        a-=rhs.a;
        return *this;
    }
    constexpr modint operator-(const modint &rhs) const noexcept{
        return modint(*this)-=rhs;
    }
    constexpr modint &operator--() noexcept{
        return --a,*this;
    }
    constexpr modint operator--(int) noexcept{
        modint t=*this; return --a,t;
    }
    constexpr modint &operator*=(const modint &rhs) noexcept{
        a=a*rhs.a%Modulus;
        return *this;
    }
    constexpr modint operator*(const modint &rhs) const noexcept{
        return modint(*this)*=rhs;
    }
    constexpr modint &operator/=(modint rhs) noexcept{
        u64 exp=Modulus-2;
        while(exp){
            if (exp&1) *this*=rhs;
            rhs*=rhs; exp>>=1;
        }
        return *this;
    }
    constexpr modint operator/(const modint &rhs) const noexcept{
        return modint(*this)/=rhs;
    }
    constexpr modint operator-() const noexcept{
        return modint(Modulus-a);
    }
    constexpr bool operator==(const modint &rhs) const noexcept{
        return a==rhs.a;
    }
    constexpr bool operator!=(const modint &rhs) const noexcept{
        return a!=rhs.a;
    }
    constexpr bool operator!() const noexcept{return !a;}
    friend constexpr modint pow(modint rhs,long long exp) noexcept{
        modint res{1};
        while(exp){
            if (exp&1) res*=rhs;
            rhs*=rhs; exp>>=1;
        }
        return res;
    }
    template<class T> friend constexpr modint operator+(T x,modint y) noexcept{
        return modint(x)+y;
    }
    template<class T> friend constexpr modint operator-(T x,modint y) noexcept{
        return modint(x)-y;
    }
    template<class T> friend constexpr modint operator*(T x,modint y) noexcept{
        return modint(x)*y;
    }
    template<class T> friend constexpr modint operator/(T x,modint y) noexcept{
        return modint(x)/y;
    }
    friend ostream &operator<<(ostream &s,const modint &rhs) noexcept{
        return s << rhs.a;
    }
    friend istream &operator>>(istream &s,modint &rhs) noexcept{
        u64 a; rhs=modint{(s >> a,a)}; return s;
    }
};

using mint=modint<MOD>;

const int MAX=3010;
vector<mint> fac(MAX),finv(MAX),inv(MAX);
void COMinit(){
    fac[0]=fac[1]=1;
    finv[0]=finv[1]=1;
    inv[1]=1;
    for (int i=2;i<MAX;++i){
        fac[i]=fac[i-1]*i;
        inv[i]=-inv[MOD%i]*(MOD/i);
        finv[i]=finv[i-1]*inv[i];
    }
}
mint COM(int n,int k){
    if (n<k||n<0||k<0) return 0;
    return fac[n]*finv[k]*finv[n-k];
}

// Be careful with the value of MAX and conducting COMinit()

int main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    COMinit();
    int N,M; cin >> N >> M;
    string S; cin >> S;
    vector<int> sum(N+1,0);
    for (int i=0;i<N;++i) sum[i+1]=sum[i]+(S[i]-'0');
    vector<pair<int,int>> sec;
    for (int i=0;i<M;++i){
        int l,r; cin >> l >> r; --l,--r;
        if (!sec.empty()&&sec.back().second>=r) continue;
        if (!sec.empty()&&sec.back().first==l) sec.pop_back();
        sec.emplace_back(l,r);
    }
    int m=sec.size();
    vector<vector<mint>> dp(m+1,vector<mint>(N+1,0));
    dp[0][0]=1;
    mint ans=0;
    int prel=-1,prer=-1;
    for (int i=0;i<m;++i){
        int l=sec[i].first,r=sec[i].second;
        int nxt=(!i?0:min(l,prer+1)-prel),add=sum[r+1]-sum[max(prer+1,l)],rest=max(0,prer-l+1);
        for (int j=0;j<=N;++j){
            if (dp[i][j]==0) continue;
            for (int k=0;k<=min(j,nxt);++k){
                if (j-k<=rest) dp[i+1][j+add-k]+=dp[i][j]*COM(nxt,k);
            }
        }
        if (i==m-1) for (int j=0;j<=N;++j){
            ans+=dp[i+1][j]*COM(r-l+1,j);
        }
        prel=l,prer=r;
    }
    cout << ans << '\n';
}

Measured memory_bytes: 29824