#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

#define WINDOW_SIZE 3

int main() {
	
	FILE *input = fopen("input", "r");

	if(input == NULL) {
		printf("oh noes couldn't open the input file lol\n");
		return 1;
	}


	char line[255];
	int index = 0, count = 0, last_num = INT_MAX;
	int windows[WINDOW_SIZE][WINDOW_SIZE];

	while(fgets(line, sizeof(line), input) != NULL) {
		int cur_num = atoi(line),
			cur_index = index % (WINDOW_SIZE);

		// Put values diagonal into the 3x3 grid, like this
		// A B C
		// B C A
		// C A B
		for(int i=0; i<WINDOW_SIZE; i++){
			int cur_col = (cur_index + i) % WINDOW_SIZE;
			windows[i][cur_col] = cur_num;
		}

		index++;
		if(index < WINDOW_SIZE) // skip first 3 values
			continue;

		// Calculate average for current column, e.g.
		// A B C
		// B C A
		// C A B
		// ^
		int sum = 0;
		for(int i=0; i<WINDOW_SIZE; i++)
			sum += windows[cur_index][i];
		
		count += sum > last_num;
		last_num = sum;
	}

	fclose(input);

	printf("There were %d measurements larger than the last.\n", count);

}