a,b = map(int,input().split())
s = input()
sw = 0
for i in range(len(s)):
    if i == a and s[i] != '-':
        sw = 1
    elif i != a and s[i] == '-':
        sw = 1
    else:
        pass
if sw == 1:
    print('No')
else:
    print('Yse')