#include <stdio.h>
#include <stdlib.h>

int main()
{
    int i,j,k,a,b,t;
    scanf("%d %d",&a,&b);
    char s[a+b+2];
    t = a;
    scanf("%s",s);
    k = 0;
    for(i = 0; i < a+b+1; i++){
        if(s[i]=='-'){
            k++;
        }
    }
    if(s[t]=='-'){
        j = 1;
    }

    if(j == 1 && k == 1){
        printf("Yes\n");
    }
    else printf("No\n");

    return 0;
}
