#include <cstdio>#include <cstdlib>#include <cstring>#include <cmath>#include <cassert>#include <iostream>#include <sstream>#include <fstream>#include <map>#include <set>#include <vector>#include <queue>#include <algorithm>#include <iomanip>#define inf 0x3f3f3f3f#define maxn 1005using namespace std;struct node{ int mm,dd,hh,MM;} ttt[maxn];char str[1005];int f[maxn][maxn],t[maxn],n;bool flag[maxn];int cmp(node t1,node t2) //t1<t2 -1; t1==t2 0; t1>t2 1;{ if(t1.mm!=t2.mm) { if(t1.mm<t2.mm) return -1; else return 1; } if(t1.dd!=t2.dd) { if(t1.dd<t2.dd) return -1; else return 1; } if(t1.hh!=t2.hh) { if(t1.hh<t2.hh) return -1; else return 1; } if(t1.MM!=t2.MM) { if(t1.MM<t2.MM) return -1; else return 1; } return 0;}int main(){ char op; while(scanf("%d",&n)!=EOF&&n!=0) { memset(flag,0,sizeof(flag)); for(int i=n; i>=1; i--) { scanf("%d:%d:%d:%d %s %c",&ttt[i].mm,&ttt[i].dd,&ttt[i].hh,&ttt[i].MM,str,&op); if(op=='+') flag[i]=1; } t[1]=0; for(int i=2; i<=n; i++) { t[i]=t[i-1]; if(cmp(ttt[i],ttt[i-1])>=0 ) t[i]++; } f[1][1]=1; if(flag[1]) f[1][0]=inf; else f[1][0]=0; for(int i=2; i<=n; i++) f[1][i]=inf; for(int i=2; i<=n; i++) { for(int j=1; j<=n; j++) f[i][j]=inf; if(!flag[i]) f[i][0]=f[i-1][0]; else f[i][0]=inf; if(flag[i]) { if(t[i]==0) f[i][i]=min(f[i][i],f[i-1][0]+1); for(int j=1; j<i; j++) if(f[i-1][j]<inf) { int tt; tt=t[i]; if(cmp(ttt[i],ttt[j])>=0) tt--; if(tt==t[j]) //zhengque queding nianfen { f[i][i]=min(f[i-1][j]+1,f[i][i]); } } } else { for(int j=1; j<=n; j++) f[i][j]=min(f[i][j],f[i-1][j]); if(t[i]==0) f[i][i]=min(f[i][i],f[i-1][0]+1); for(int j=1; j<i; j++) if(f[i-1][j]<inf) { int tt; tt=t[i]; if(cmp(ttt[i],ttt[j])>=0) tt--; if(tt==t[j]) //zhengque queding nianfen { f[i][i]=min(f[i-1][j]+1,f[i][i]); } } } } int res; res=inf; for(int i=1; i<=n; i++) res=min(res,f[n][i]); res=min(res,n); printf("%dn",res); } return 0;}
