#include <stdio.h>
//練習問題E
int tri(int n){
	if(n==0){
		return 0;
	}
	else if (n==1){
		return 0;
	}
	else if (n==2){
		return 1;
	}
	else {
		return tri(n-1)+tri(n-2)+tri(n-3);
	}
}
 
 
 
int main(void) {
	int n = 7;
    printf("数列Tnについて, n=%dのときの値は%d\n", n
, tri
(n
)); 	return 0;
}
 
				I2luY2x1ZGUgPHN0ZGlvLmg+Ci8v57e057+S5ZWP6aGMRQppbnQgdHJpKGludCBuKXsKCWlmKG49PTApewoJCXJldHVybiAwOwoJfQoJZWxzZSBpZiAobj09MSl7CgkJcmV0dXJuIDA7Cgl9CgllbHNlIGlmIChuPT0yKXsKCQlyZXR1cm4gMTsKCX0KCWVsc2UgewoJCXJldHVybiB0cmkobi0xKSt0cmkobi0yKSt0cmkobi0zKTsKCX0KfQoKCgppbnQgbWFpbih2b2lkKSB7CglpbnQgbiA9IDc7CiAgICBwcmludGYoIuaVsOWIl1Ru44Gr44Gk44GE44GmLCBuPSVk44Gu44Go44GN44Gu5YCk44GvJWRcbiIsIG4sIHRyaShuKSk7CglyZXR1cm4gMDsKfQo=