A：签到
#include<iostream> #include<cstdio> #include<cmath> #include<cstdlib> #include<cstring> #include<algorithm> using namespace std; int read() { int x=0,f=1;char c=getchar(); while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();} while (c>='0'&&c<='9') x=(x<<1)+(x<<3)+(c^48),c=getchar(); return x*f; } #define N 100010 int n,l,m; struct data{int x,y; }a[N]; int main() { n=read(),l=read(),m=read(); for (int i=1;i<=n;i++) { int x=read(),y=read(); a[i].x=x,a[i].y=x+y; } a[0].x=a[0].y=0,a[n+1].x=a[n+1].y=l; int ans=0; for (int i=1;i<=n+1;i++) ans+=(a[i].x-a[i-1].y)/m; cout<<ans; return 0; }