int main(void) {
    int a,b;
    char s[100];
    scanf("%d%d",&a,&b);
    scanf("%s",s);
    if (s[a] != '-' || s[1] == '-' || strlen(s) != a + b + 1) {
        printf("No\n");
        return 0;
    } else {
        puts("Yes");
    }
    
    return 0;
}
