#include <iostream>
#include <cstring>
#include <algorithm>
#include <vector>
#include <string>
#include <math.h>
#include <iomanip>
#include <limits>
#include <list>
#include <queue>
#include <tuple>
#include <map>
#include <stack>
#include <set>
using namespace std;
#define MOD (long long int)(1e9+7)
#define ll long long int
#define rep(i,n) for(int i=0; i<(int)(n); i++)
#define reps(i,n) for(int i=1; i<=(int)(n); i++)
#define REP(i,n) for(int i=n-1; i>=0; i--)
#define REPS(i,n) for(int i=n; i>0; i--)
#define INF (int)(1123456789)
#define LINF (long long int)(112345678901234567)
#define chmax(a, b) a = (((a)<(b)) ? (b) : (a))
#define chmin(a, b) a = (((a)>(b)) ? (b) : (a))
#define all(v) v.begin(), v.end()

const int N = (int)3e5;

ll mpow(ll a, ll b){
  if(b==0) return 1;
  else if(b%2==0){ll memo = mpow(a,b/2); return memo*memo%MOD;}
  else return mpow(a,b-1) * a % MOD;
}
ll lpow(ll a, ll b){
  if(b==0) return 1;
  else if(b%2==0){ll memo = lpow(a,b/2); return memo*memo;}
  else return lpow(a,b-1) * a;
}
ll gcd(ll a, ll b){
  if(b==0) return a;
  else return gcd(b, a%b);
}
vector<ll> kaijo_memo;
ll kaijo(ll n){
  if(kaijo_memo.size() > n) return kaijo_memo[n];
  if(kaijo_memo.size() == 0) kaijo_memo.push_back(1);
  while(kaijo_memo.size() <= n) kaijo_memo.push_back(kaijo_memo[kaijo_memo.size()-1] * kaijo_memo.size() % MOD);
  return kaijo_memo[n];
}
vector<ll> gyaku_kaijo_memo;
ll gyaku_kaijo(ll n){
  if(gyaku_kaijo_memo.size() > n) return gyaku_kaijo_memo[n];
  if(gyaku_kaijo_memo.size() == 0) gyaku_kaijo_memo.push_back(1);
  while(gyaku_kaijo_memo.size() <= n) gyaku_kaijo_memo.push_back(gyaku_kaijo_memo[gyaku_kaijo_memo.size()-1] * mpow(gyaku_kaijo_memo.size(), MOD-2) % MOD);
  return gyaku_kaijo_memo[n];
}

ll nCr(ll n, ll r){
  if(n == r) return 1;//0個の丸と-1個の棒みたいな時に時に効く？不安.
  if(n < r || r < 0) return 0;
  ll ret = 1;
  ret *= kaijo(n); ret %= MOD;
  ret *= gyaku_kaijo(r); ret %= MOD;
  ret *= gyaku_kaijo(n-r); ret %= MOD;
  return ret;
}


int main(void){
  ll n,m;
  cin>>n>>m;
  string s; cin>>s;
  vector<ll> ones,zeros;
  ones.push_back(0);
  zeros.push_back(0);
  rep(i,s.size()){
    ones.push_back(ones[i] + s[i] - '0');
    zeros.push_back(zeros[i] + '1' - s[i]);
  }
  vector<pair<ll,ll>> com;
  ll mr = -1;
  rep(i,m){
    ll l,r;cin>>l>>r; l--;r--;
    if(i > 0 && com.back().first == l){
      if(com.back().second < r){
        com.pop_back();
      }
    }
    if(mr < r){
      com.push_back({l,r});
      mr = r;
    }
  }
  com.push_back({LINF,LINF});
  vector<ll> L,R;
  rep(i,com.size()){
    L.push_back(com[i].first);
    R.push_back(com[i].second);
  }
  int ci = 0;
  vector<vector<ll>> dp;
  rep(i,s.size()+1){
    dp.push_back(vector<ll>());
    rep(j,s.size()+1){
      dp[i].push_back(0);
    }
  }
  dp[0][0] = 1;
  rep(i,s.size()){
    if(L[ci+1] <= i){
      ci++;
    }
    ll l = L[ci];
    ll r = R[ci];
    if(r < i || l > i){
      r = i;
    }
    rep(j,s.size()){  
      if(zeros[r+1] >= (i+1) - j){
        dp[i+1][j] += dp[i][j];
        dp[i+1][j] %= MOD;
      }
      if(ones[r+1] >= j+1){
        dp[i+1][j+1] += dp[i][j];
        dp[i+1][j+1] %= MOD;
      }
      
    }
  }
  cout<<dp[n][ones.back()]<<endl;
  /*rep(i,n+1){
    rep(j,n){
      cout<<dp[i][j]<<" ";
    }
    cout<<endl;
  }*/
  return 0;
}


Measured memory_bytes: 82944