麻烦各位大佬帮我看看，5 7 8 9wa了

#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main() {
float a;
	int t, n,b;
	int d[2000001] = { 0 };
	scanf("%d", &n);
	for (int i = 0; i < n; i++) {
		scanf("%f %d",&a,&t);
		for (int j = 1; j <= t; j++) {
			b = a * j;
			if (d[b] == 0)
				d[b] = 1;
			else 
				d[b] = 0;
		}
	}
	for (int w = 0; w < 2000001; w++) {
		if (d[w] == 1) {
			printf("%d", w);
			break;
		}
	}
	return 0;



}