# --*-- encoding:utf-8 --*--

ab = list(map(int, input())).split(" ")
code = input()

notflag = False
for i in range(a):
	if( code[i] not in "123456789" ):
        notflag = True

if( code[a] != "-" ):
	notflag = True

for i in range(a+1, b):
	if( code[i] not in "123456789" ):
		notflag = True

if(notflag == False):
	print "Yes"
elif:
	print "No"
	