# n =  int(input());
s = 0;
for i in range(1,1000):
    a = i // 100;
    b = i // 10 % 10;
    c = i % 10;
    if a == 3 or b == 3 or c == 3:
        s += 1;
print(s);




/**************************************************************
	Problem: 1056
	User: admin
	Language: Python
	Result: Runtime Error
****************************************************************/