zoj 2173 Flow Layout

#include<stdio.h>int main(){    int n, w, h;    while (scanf("%d", &n), n)    {        int width = -1, height = 0, cw = 0, ch = -1;        while (scanf("%d %d", &w, &h), w != -1 && h != -1)        { if (cw + w > n) {     height += ch;     if (cw > width)         width = cw;     cw = w;     ch = h; } else {     if (h > ch)         ch = h;     cw += w; }        }        if (cw > width) width = cw;        height += ch;        printf("%d x %dn", width, height);    }    return 0;}