#include <bits/stdc++.h>
using namespace std;
int main() {
  int a, b;
  char s[100];
  cin >> a >> b;
  scanf("%s", s);
  bool judge = true;
  int i = 0;
  for (; i < a; i++) {
    if (s[i] == '-') {
      judge = false;
    }
  }
  if (s[i] != '-') {
    judge = false;
  }
  for (; i < a + b + 1; i++) {
    if (s[i] == '-') {
      judge = false;
    }
  }
  if (s[i] == '\0') judge = false;
  if (judge)
    printf("Yes\n");
  else
    printf("No\n");
}
