#include <iostream>
#include <vector>

using namespace std;

int main(){
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  f = 1;
  for(int i = 0; i < a; i++){
    if(s[i] - '0' < 0 || s[i] - '0' > 9){
      f = 1;
      break;
    }
  }
  if(s[a] != '-') f = 1;
  for(int i = a+1; i < b; i++){
    if(s[i] - '0' < 0 || s[i] - '0' > 9){
      f = 1;
      break;
    }
  }
  if(f) cout << "No";
  else cout << "Yes";
}