#include <stdio.h>
#include <string.h>

void edit_line(char *buffer, int current_line) {
	for (int i = 0; i < current_line; i++) {
		buffer = strchr(buffer, '\n') + 1;
	}

	char *line_end = strchr(buffer, '\n');
	char saved[1024] = {0};
	strcpy(saved, line_end);
	scanf("%s", buffer);
	strcpy(buffer + strlen(buffer), saved);
}

int main(int argc, char **argv) {
	char buffer[1024] = { 0 };

	FILE *f = fopen(argv[1], "r");
	fread(buffer, sizeof(buffer), 1, f);
	fclose(f);

	printf("Contents:\n%s\n", buffer);

	int current_line = 0;
	scanf("%d", &current_line);
	edit_line(buffer, current_line);

	f = fopen(argv[1], "w");
	fwrite(buffer, strlen(buffer), 1, f);
	fclose(f);

	return 0;
}