#include <bits/stdc++.h>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define repm(i, m, n) for (int i = (m); i < (int)(n); i++)
#define repr(i, n) for (int i = (n); i > 0; i--)
#define all(vec) vec.begin(), vec.end()
using namespace std;

int main(){
  int a, b;
  string c;
  cin >> a >> b >> c;

  //int ans = 0;
  string ans = "Yes";
  rep(i, a + b + 1){
    if (i != a){
      if (d[i] == '-') ans = "No";
    }
    else{
      if (d[i] != '-') ans = "No";
    }
  }
  
  cout << ans << endl;
}