1     #include<iostream> 2     #include<algorithm> 3     #include<set> 4     #include<cstdio> 5     #include<cstdlib> 6     #include<cmath> 7     using namespace std; 8     #define FOR(i,j,k) for(int i=j;i<=k;i++) 9     #define FORD(i,j,k) for(int i=j;i>=k;i--)10     #define LL long long11     #define SZ(x) int(x.size())12     #define maxn 501013     int n;14     int a[maxn];15     int fz(int l,int r,int v)16     {17         if(l<=r)18         {19         /*int ss=999999;20         int s=0;21         FOR(i,l,r)22         if(a[i]<ss) {ss=a[i];s=i;}23         return min(r-l+1,fz(l,s-1,ss)+fz(s+1,r,ss)+ss-v);*/24         int m=min_element(a+l,a+r+1)-a;25         return min(r-l+1,fz(l,m-1,a[m])+fz(m+1,r,a[m])+a[m]-v);26         }27         else return 0;28     }29     30     int main()31     {32     cin>>n;33     FOR(i,1,n)34     cin>>a[i];35     cout<<fz(1,n,0);36     return 0;37     }38