#include <stdio.h> int main() { int a, b, i, tot, c1, c2; scanf( "%d%d", &a, &b ); tot = 0; for ( i = a; i <= b; i++ ) { c1 = i / 10; c2 = i % 10; if ( (c1 + c2) % 3 == 0 ) tot++; } printf( "%d\n", tot ); return(0); }

输入：7 31

输出：_________