import copy
a,b = map(int, input().split())
s = list(input())
tmp = copy.copy(s)
tmp.pop(a)
if 1 <= a and b <= 5 and a + b + 1 == len(s) and s[a] == '-' and ''.join(tmp).isnumeric():
    print('yes')
else:
    print('No')
    