#include <bits/stdc++.h>
using namespace std;
int main(void) {
  int A, B;
  cin >> A >> B;
  string s;
  cin >> s;
  int check = 0;
  for (int i = 0; i < A + B; i++)
    if (s[i] >= '0' && s[i] <= '9') check++;
  if (s[A] != '-' || check <= A + B)
    cout << "No" << endl;
  else
    cout << "Yes" << endl;
  return 0;
}
