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

#define LINES 1000

int compare(const void *a, const void *b);

int main()
{
	int new;
	int old;
	int safe = 0;
	FILE *input;
	input = fopen("./input", "r");
	// read number. Compare next number (higher, lower, +-1-2)
	// if you get to newline, ++
	for (int i = 0; i < LINES; i++) {
		int rising = 0;
		int first = 1;
		fscanf(input, "%d", &old);
		char nextChar = 0;
		while ((nextChar = fgetc(input)) && nextChar != '\n') {
			fscanf(input, "%d", &new);
			// if difference isnt 1-3
			if (abs(new - old) > 3 || abs(new - old) < 1) {
				while(getc(input) != '\n');
				goto loopEnd;
			}
			// only for first comparison of row. Set direction.
			if (first && ((new - old) < 0)) rising = 0; else if (first) rising = 1;
			// for other comparisons, compare current direction to the previous.
			if (!first && (rising != !((new - old) < 0))) {
				// printf("rising: %d while %d - %d is %d\n", rising, new, old, new - old);
				while(getc(input) != '\n');
				goto loopEnd;
			}
			// get ready for the next comparisons!
			first = 0;
			old = new;
		}
		safe++;
		loopEnd:
	}
	printf("%d\n", safe);
}