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