NOIP '04 P3 - Chorus Formation
View as PDF students stand in a row, and the music teacher asks 
 students to leave so that the remaining 
 students form a chorus formation.
The chorus formation refers to such a formation: Suppose the  students left are numbered 
 from left to right, and their heights are 
 respectively, then their heights satisfy 
 
.
Your task is, given the heights of all  students, calculate the minimum number of students who need to leave, so that the remaining students can form a chorus formation.
Input Specification
The first line of the input consists of an integer  
 denoting the number of students. The second line consists of 
 integers separated by a single space denoting the height of the 
-th student. The heights satisfy 
.
Output Specification
Output the minimum number of students that should leave to form a chorus formation.
Sample Input
8
186 186 150 200 160 130 197 220
Sample Output
4
Constraints
For  of test cases, 
.
For all test cases, .
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