#pragma GCC optimize("Ofast")
#pragma GCC target("avx2")

char*mmap();
char wbuf[1<<25];

#define rd_skip_line() while(*rp++!=10)
#define rd(v) long v=0;{long _c;while(_c=*rp++-48,_c>=0)v=v*10+_c;}
#define WTHI(v) {long _z=v,_n=0,_d=0;while(++_n,_d=_d<<8|0x30|_z%10,_z/=10);*(long*)wp=_d;wp+=_n;}
#define WTLO(v) {long _z=v,_n=8,_d=0;while(_d=_d<<8|0x30|_z%10,_z/=10,--_n);*(long*)wp=_d;wp+=8;}
#define wt(v) if(v>=100000000){WTHI(v/100000000);WTLO(v);}else{WTHI(v);}

char a[500001];

main(){
	char*rp=mmap(0l,1l<<25,1,2,0,0ll);
	char*wp=wbuf;
	long z=0;
	rd_skip_line();
	while(*rp){
		rd(l);
		rd(r);
		for(;l<=r;++l){
			z+=(a[l]^=1)?1:-1;
		}
		wt(z);
		*wp++='\n';
	}
	write(1,wbuf,wp-wbuf);
	_exit(0);
}