#include <bits/stdc++.h>
using namespace std;

int main() {
  long a,b;
  string s,ans="Yes";
  cin >> a >> b >> s;
  for(int i=0;i<a+b+1;i++) {
    if(i!=a&&s[i]=='-') ans="No";
    if(i==a&&s[i]!='-') ans="No";
  }
  cout << ans << endl;
}