#include <bits/stdc++.h>
int main() {
  int a, b;
  scanf("%d %d", &a, &b);
  int size = a + b + 1;
  char str[100];
  scanf("%s", str);
  int i, count = 0;
  int check;
  for (i = 0; i < size; i++) {
    if (str[a] == '-') {
      check = 1;
    }
  }
  if (check == 1) {
    for (i = 0; i < size; i++) {
      if (str[i] >= '0' && str[i] <= '9') {
        count++;
      }
    }
    if (count == size - 1) {
      printf("Yes\n");
    } else {
      printf("No\n");
    }
  } else {
    printf("No\n");
  }
  return 0;
}
