#include <bits/stdc++.h>
int main() {
  int a, b;
  scanf("%d %d", &a, &b);
  int flag = 0;
  char str[a + b + 1];
  scanf("%s", str);
  int atr = 0;
  for (int i = 0; i < a + b + 1; i++) {
    if (str[a] != '-') {
      flag = 1;
    }
    if (str[i] >= '0' && str[i] <= '9') {
      ++atr;
    }
  }
  int total = a + b;
  if (atr == total) {
    printf("Yes\n");
  } else {
    printf("No\n");
  }
  return 0;
}
