[UVa514] Rails

/*
    Source: UVa514
    Status: AC
    Done: 19/11/2015
    Remarks: stack
*/
#include<cstdio>
using namespace std;
int b[1005],c[1005];
int main()
{
    int top,n,i,cur;
    while(1){
        scanf("%d",&n);
        if(n==0)break;
        while(1){
            top=0;
            scanf("%d",&b[1]);
            if(b[1]==0){
                printf("\n");
                break;
            }
            for(i=2;i<=n;i++){
            scanf("%d",&b[i]);
            }
            cur=1;
            top=0;
            for(i=1;i<=n;i++){
                if(i!=b[cur]){
                    c[++top]=i;//insert elements in the stack
                       //cur++;
                   }
                   else cur++;
                while(top && c[top] == b[cur])//stack is not empty
                {
                    top--;//delete elements in the stack
                    cur++;
                }
            }
            if(!top) printf("Yes\n");
            else     printf("No\n");
        }
    } 
    return 0;
}