#include <bits/stdc++.h>
int max(int a, int b) { return a >= b ? a : b; }
int min(int a, int b) { return b >= a ? a : b; }
int sei(int a) { return a > 0 ? a : 0; }
int factorial(int n) {
  if (n > 0)
    return n * factorial(n - 1);
  else
    return 1;
}
int compare_up_int(const void *a, const void *b) {
  return *(int *)a - *(int *)b;
}
int compare_down_int(const void *a, const void *b) {
  return *(int *)b - *(int *)a;
}
int euclid(int a, int b) {
  if (a < b) {
    int tmp = a;
    a = b;
    b = tmp;
  }
  int r = a % b;
  if (r < 0) r += b;
  while (r != 0) {
    a = b;
    b = r;
    r = a % b;
    if (r < 0) r += b;
  }
  return b;
}
int main() {
  int a, b, count = 0;
  char c[20];
  scanf("%d %d", &a, &b);
  scanf("%s", c);
  for (int i = 0; i < a + b + 1; i++) {
    if (c[i] == '-') count++;
  }
  if (count == 1)
    printf("Yes");
  else
    printf("No");
  return 0;
}
