#include #define ll long long #define mod 1000000007 using namespace std; inline int read() {int x=0,f=0; char c=getchar(); while (c<'0'||c>'9') {if (c=='-') f=1; c=getchar(); } while (c>='0'&&c<='9') x=x*10+c-'0',c=getchar(); if (f) x=-x; return x; } int a[200005],n,m; int lf[100005],rg[100005]; ll s[200005]; struct towns {int p,x; }t[200005]; struct cloud {int y,r; }p[100005]; inline bool cmp(towns a,towns b) {return a.x>1; if (t[mid].x>1; if (t[mid].x>p[i].y+p[i].r) {r=mid-1;} else {l=mid+1;} } rg[i]=r; a[lf[i]]++; a[rg[i]+1]--; } ll ans=0; for (i=1;i<=n;i++) {a[i]+=a[i-1];s[i]=s[i-1]; if (a[i]==0) ans+=t[i].p; if (a[i]==1) s[i]+=t[i].p; } ll maxn=0; for (i=1;i<=m;i++) {maxn=max(maxn,s[rg[i]]-s[lf[i]-1]);} ans+=maxn; printf ("%lld\n",ans); return 0; }