n = 7000 
f = 0
peb = 0
instructions = input()
ins = list(instructions)

for i in range(n):
    if ins[i] == "(":
        f += 1
    else: 
        f -= 1
    if f == -1: 
        pob = i; 
        break;

print(pob+1) # variables start from zero or sum shit