import re

[A, B] = map(int,raw_input().split())
S_array = list(raw_input())

i = 0
ret = "Yes"

while i < len(S_array):
    item = S_array.pop(0)
#    print item
    if(i < A):
        if re.match('-', item):
            ret = "No"
            break
    if(i == A):
        if re.match("[^-]", item):
            ret = "No"
            break

    if(i > A):
        if re.match("-", item):
            ret = "No"
            break

    i = i + 1


print ret
