#include <bits/stdc++.h>
#include <math.h>
#define rep(i, n) for(int i = 0; i < n; ++i)
using namespace std;

int main() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  bool b = 1;
  rep(i, s.size()){
    if(i == a){
      if(s[i] != '-'){
        b = 0;
        break;
      }
    }
    else if(s[i] >= '0' && s[i] <= '9') continue;
    else{
      b = 0;
      break;
    }
  }
  if(b) cout << "Yes" << endl;
  else cout << "No" << endl;
  return 0;
}