a,b = map(int,input().split())
s = input()
s_list = s
s_list = list(s_list)
flg = False
cnt = 0

for i in range(len(s_list)):
    if s_list[i] == '-':
        flg = True
    elif s_list[i].isdecimal():
        cnt += 1



if flg:
    if cnt == a + b:
        print('Yes')
    else:
        print('No')
else:
    print('No')
