#include <cstdio>

int main() {
	int zeros = 0;
	int ones = 0;
	int last = -1;

	char c1, c2;
	while (scanf("%c%c", &c1, &c2) == 2) {
		if (c1 == '+' && c2 == '-') {
			if (last != 1)
				ones++;
			last = 1;
		} else {
			if (last != 0)
				zeros++;
			last = 0;
		}
		// printf("%d %d\n", ones, zeros);
	}

	printf("%d\n", ones < zeros ? ones : zeros);

	return 0;
}