Based on the news about the stock in the past five trading days, please predict the rise or fall of the stock in the next trading day. If the stock is predicted to rise in the next trading day, please output [Rise], if the stock is predicted to fall in the next trading day, please output [Decrease].

Date:2018-09-26, Stock:RIO, The news for the past five days is as follows:
2018-09-19: NEWS1: Rio Tinto Details $3.2 Bln Share Buy-back.NEWS2: Rio Tinto Details $3.2 Bln Share Buy-back.NEWS3: European markets open higher, brushing off trade dispute.
2018-09-20: NEWS1: Energy Sector Update for 09/20/2018: LGCY,NOA,NOA.TO,RIO,RRC.NEWS2: Energy Sector Update for 09/20/2018: LGCY,NOA,NOA.TO,RIO,RRC.NEWS3: Energy Sector Update for 09/20/2018: NOA,NOA.TO,RIO,RRC.NEWS4: Energy Sector Update for 09/20/2018: NOA,NOA.TO,RIO,RRC.NEWS5: Energy Sector Update for 09/20/2018: USO, UNG, RIO.NEWS6: Energy Sector Update for 09/20/2018: USO, UNG, RIO.NEWS7: Pre-Market Most Active for Sep 20, 2018 :  CRON, MU, TLRY, GE, EUFN, QQQ, NIO, CGC, BABA, BOTZ, EQNR, RIO.NEWS8: Pre-Market Most Active for Sep 20, 2018 :  CRON, MU, TLRY, GE, EUFN, QQQ, NIO, CGC, BABA, BOTZ, EQNR, RIO.NEWS9: [$$] Rio Tinto details $3.2bn share buyback.NEWS10: Rio Tinto announces new $3.2 billion share buyback, stock rises.NEWS11: Rio Tinto announces new $3.2 billion share buyback, stock rises.NEWS12: European shares add to gains as trade war fears fade.NEWS13: [$$] Opening Quote: Kier determined not to be the next Carillion .NEWS14: [$$] Rio Tinto issues details on returning $3.2bn to shareholders.NEWS15: [$$] Rio Tinto Plans Buybacks to Return Cash to Shareholders.
2018-09-21: NEWS1: Company News For Sep 21, 2018.NEWS2: Company News For Sep 21, 2018.NEWS3: Company News For Sep 21, 2018.NEWS4: Asian Shares Extend Recovery; China Leads Gains.NEWS5: Asian Shares Extend Recovery; China Leads Gains.
2018-09-24: NEWS1: Asian Shares Fall As New US Tariffs Take Effect.NEWS2: Asian Shares Fall As New US Tariffs Take Effect.
2018-09-25: nan

Answer: Decrease